Industrial activities such as smelting emissions,mineral combustion and industrial wastewater discharge might lead to copper pollution in the environment.This kind of copper pollution has harmful effects on aquatic o ...Industrial activities such as smelting emissions,mineral combustion and industrial wastewater discharge might lead to copper pollution in the environment.This kind of copper pollution has harmful effects on aquatic o rganisms,plants and animals through direct or indirect exposure.However,the current understanding of the toxicity of copper is rather limited.Copper overload can perturb intracellular homeostasis and induce oxidative stress and e ven cell death.Recently,cuproptosis has been identified as a copper-dependent form of cell death induced by o xidative stress in mitochondria.We uncover here that zinc transporter 1(ZNT1)is an important regulator involved in cuproptosis.Firstly,we established the copper overload-induced cell death model with the overexpression of copper importer SLC31A1 in HeLa cells.Using this model,we conducted unbiased genome-wide CRISPR-Cas9 screens in cells treated with copper.Our results revealed a significant enrichment of ZNT1 gene in both library A and library B plasmids.Knocking out of ZNT1 in HeLa cells notably prevented cuproptosis.Subsequent knockout of metal transcription factor 1(MTF1)in ZNT1-deficient cells nearly abolished their ability to resist copper-induced cell death.However,overexpression of metallothionein 1X(MT1X)in the double-knockout cells could p artially restored the resistance to cuproptosis by loss of MTF1.Mechanistically,knockout of ZNT1 could promote MT1X expression by activating MTF1.As a consequence,the interaction between MT1X and copper was e nhanced,reducing the flow of copper into mitochondria and eliminating mitochondria damage.Taken together,this study reveals the important role of ZNT1 in cuproptosis and shows MTF1-MT1X axis mediated resistance to c uproptosis.Moreover,our study will help to understand the regulatory mechanism of cellular and systemic copper homeostasis under copper overload,and present insights into novel treatments for damages caused by both genetic copper overload diseases and environmental copper contamination.展开更多
The bioleaching of molybdenum from its sulfide ore using a Mo-resistant thermophilic bacterium sulfolobus metallics combined with a membrane biological reactor（MBR） was studied.The experimental results showed that t...The bioleaching of molybdenum from its sulfide ore using a Mo-resistant thermophilic bacterium sulfolobus metallics combined with a membrane biological reactor（MBR） was studied.The experimental results showed that the concentration of Mo can be controlled by filter of the membrane in MBR and the toxicity of Mo to microorganism is decreased in the process of bioleaching.It was also evidenced that there were different leaching rates of Ni and Mo when the concentration of Mo was different.After leaching for 20 d in the MBR at Mo concentration of 395 mg/L,the leaching rates of Ni and Mo reached the maximum of 79.57% and 56.23% respectively under the conditions of 100 g/L of mineral density,65 ℃,pH=2 and 1.0 L/min of the aeration rate.While 75.59% Ni and 54.33% Mo were leached out in column without membrane under the same conditions.展开更多
A novel cDNA sequencehtMT2, which encodes a type 2 metallothionein_like protein, was isolated from Helianthus tuberosus L. tuber cDNA library. The whole sequence is 509 bp, including an open reading frame (ORF) of 240...A novel cDNA sequencehtMT2, which encodes a type 2 metallothionein_like protein, was isolated from Helianthus tuberosus L. tuber cDNA library. The whole sequence is 509 bp, including an open reading frame (ORF) of 240 bp, a 5′ UTR of 62 bp and a 3′ UTR of 207 bp. Two genomic sequences covering the coding region ofhtMT2were cloned by PCR reaction. Sequence analysis revealed that the genomic sequences htMTG_1 of 986 bp and htMTG_2 of 982 bp were both composed of three exons and two introns. The deduced protein consisted of 79 amino acid residues with a predicted molecular weight of 7.8 ku (kD). Amino_terminal and carboxy_terminal domains contained 8 and 7 cysteine residues respectively, separated by a central cysteine free spacer. Sequence alignment revealed that the predicted protein ofhtMT2 was homologous to type 2 metallothioneins (MTs) of plants. Southern blotting analysis indicated that htMT2was encoded by a small multi_gene family in H. tuberosus genome. Northern blotting analysis showed that htMT2 transcripts were detected in stems, leaves and leafstalks, but no transcripts were detected in roots. The expression level in stems was the highest among the above tissues. Transcripts in stems were significantly reduced by Cu 2+ treatment. Judging from the homologies between the deduced HtMT2 and other type 2 plant metallothioneins as well as responses to metal ions, we believe thatwere cloned by PCR reaction. Sequence analysis revealed that the genomic sequences htMTG_1 of 986 bp and htMTG_2 of 982 bp were both composed of three exons and two introns. The deduced protein consisted of 79 amino acid residues with a predicted molecular weight of 7.8 ku (kD). Amino_terminal and carboxy_terminal domains contained 8 and 7 cysteine residues respectively, separated by a central cysteine free spacer. Sequence alignment revealed that the predicted protein ofhtMT2 was homologous to type 2 metallothioneins (MTs) of plants. Southern blotting analysis indicated that htMT2was encoded by a small multi_gene family in H. tuberosus genome. Northern blotting analysis showed that htMT2 transcripts were detected in stems, leaves and leafstalks, but no transcripts were detected in roots. The expression level in stems was the highest among the above tissues. Transcripts in stems were significantly reduced by Cu 2+ treatment. Judging from the homologies between the deduced HtMT2 and other type 2 plant metallothioneins as well as responses to metal ions, we believe that[ShtMT2 encodes a new type 2 metallothionein.展开更多
Rice metallothionein-like protein (rgMT) shows characteristics of a three-section pattern composed of two highly conserved cysteine rich (CR) domains in the terminals and a spacer without cysteine (cys) residues in th...Rice metallothionein-like protein (rgMT) shows characteristics of a three-section pattern composed of two highly conserved cysteine rich (CR) domains in the terminals and a spacer without cysteine (cys) residues in the center of the molecule. In this paper, the two CR domains and the spacer region were modeled by the distance geometry and homology methods separately. For the CR domains, twenty random models were generated for each cys combination based on the constraint conditions of CXC (C represents cys, X represents any amino acid other than cys), and CXXC motifs and a metal-sulfur chelating cluster. Four models for the N-terminal and two for C-terminal CR domain containing metal chelating structures formed by different combinations of cys were selected from 900 possible conformations. The GOR method was used to predict the secondary structure of the spacer region and its model was built by the homology method. After three parts of the protein were modeled, they were connected to form a three-dimensional structure model of rgMT. The whole conformation showed that rgMT could form two independent metal-sulfur chelating structures connected by a spacer peptide, without a structural or energy barrier for them to form two independent metal-chelating clusters just as mammalian metallothionein (MT) proteins. As all plant metallothionein-like (MT-L) proteins have the same primary structural characteristic, two CR domains connected by a spacer region, and many have the same cys arrangement pattern as rgMT, the three-dimensional structure model of rgMT will provide an important reference for the structural study of other plant MT-L proteins.展开更多
The corrosion behaviours of die-cast AZ91D magnesium alloys were investigated in 0.1 mol/L sodium sulphate （Na 2 SO 4 ） solutions with different pH values. The corrosion rates, morphologies, and compositions of the ...The corrosion behaviours of die-cast AZ91D magnesium alloys were investigated in 0.1 mol/L sodium sulphate （Na 2 SO 4 ） solutions with different pH values. The corrosion rates, morphologies, and compositions of the corrosion products were studied by means of scanning electron microscopy （SEM）, Fourier transform infrared spectroscopy （FTIR）, and X-ray diffractometry （XRD）. The results indicate that the order of corrosion rates in Na 2 SO 4 solutions with various pH values is pH 2pH 4pH 7pH 9pH 12. The corrosion rates in acidic solutions are higher than those in alkaline solutions, and the corrosion products are mainly magnesium hydroxide （Mg（OH） 2 ） and hydrated sulphate pickeringite （MgAl 2 （SO 4 ） 4 ·22H 2 O）. The results also indicate that the solution pH can influence the corrosion rate and morphology of corrosion products. Chloride ions and sulphate ions have different pitting initiation time.展开更多
With the progress of plant genome research, more than 50 plant metallothionein_like (MT_L) genes have been found, but only several MT_L proteins have been detected and no experimental structural information for MT_L p...With the progress of plant genome research, more than 50 plant metallothionein_like (MT_L) genes have been found, but only several MT_L proteins have been detected and no experimental structural information for MT_L proteins has been reported so far. Since detailed knowledge of the protein tertiary structure is required to understand its biological function, a method is needed to determine the structure of these proteins. In this study, the structural data of known mammal MT was used to determine the interatomic distance constraints of the CXC and CXXC motifs and the metal_sulfur chelating cluster. Then several possible MT conformations were predicted using a distance geometry algorithm. The statistical analysis was used to select those with much lower target function values and lower conformation energies as the predicted tertiary structural models of the cysteine_rich (CR) domains of these proteins. A suitable prediction method for modeling the CR domain of the plant MT_L protein was constructed. The accurately predicted result for the known structure of an MT protein from blue crab suggests that this method is practicable. The tertiary structures of CR domains of rape MT_L protein LSC54 was then modeled with this method.展开更多
Bioleaching is regarded as an essential technology to treat low grade minerals,with the distinctive superiorities of lower-cost and environment-friendly compared with traditional pyrometallurgy method.However,the biol...Bioleaching is regarded as an essential technology to treat low grade minerals,with the distinctive superiorities of lower-cost and environment-friendly compared with traditional pyrometallurgy method.However,the bioleaching efficiency is unsatisfactory owing to the passivation film formed on the minerals surface.It is of particular interest to know the dissolution and passivation mechanism of sulfide minerals in the presence of microorganism.Although bioleaching can be useful in extracting metals,it is a double-edged sword.Metallurgical activities have caused serious environmental problems such as acid mine drainage(AMD).The understanding of some common sulfide minerals bioleaching processes and protection of AMD environment is reviewed in this article.展开更多
The leaching of low-sulfur Ni-Cu matte in acid-oxygen(CuSO4-H2SO4-O2)solution at atmospheric pressure was researched.This matte was obtained from high grade Ni-Cu matte by magnetic separation,which mainly contained Ni...The leaching of low-sulfur Ni-Cu matte in acid-oxygen(CuSO4-H2SO4-O2)solution at atmospheric pressure was researched.This matte was obtained from high grade Ni-Cu matte by magnetic separation,which mainly contained Ni-Cu alloy and a small quantity of sulfides.The effects of temperature,agitation speed,oxygen flow rate,particle size,acid concentration and concentration of copper ion were studied.It is found that the matte particles are leached by shrinking core mechanism and the leaching process is electrochemically controlled.In a temperature range of 30-60℃,the surface reaction is rate-limiting step,with an apparent activation energy of 41.9 kJ/mol.But at higher temperature(70-85℃),the rate process is controlled by diffusion through the product layer,with an apparent activation energy of 7.3 kJ/mol.展开更多
The continued effect of the pyrite-tailing oxidation on the mobility of arsenic, lead, zinc, cadmium, and copper was studied in a carbonated soil under natural conditions, with the experimental plot preserved with a l...The continued effect of the pyrite-tailing oxidation on the mobility of arsenic, lead, zinc, cadmium, and copper was studied in a carbonated soil under natural conditions, with the experimental plot preserved with a layer of tailing covering the soil during three years. The experimental area is located in Southern Spain and was affected by a pyrite-mine spill. The climate in the area is typically Mediterranean, which determines the rate of soil alteration and element mobility. The intense alteration processes that occurred in the soil during three years caused important changes in its morphology and a strong degradation of the main soil properties. In this period, lead concentrated in the first 5 mm of the soil, with concentrations higher than 1500 mg kg?1, mainly associated to the neoformation of plumbojarosite. Arsenic was partially leached from the first 5 mm and mainly concentrated between 5–10 mm in the soil, with maximum values of 1239 mg kg-1; the retention of arsenates was related to the neoformation of iron hydroxysulfates (jarosite, schwertmannite) and oxyhydroxides (goethite, ferrihydrite), both with a variable degree of crystallinity. The mobility of Zn, Cd, and Cu was highly affected by pH, producing a stronger leaching in depth; their retention was related to the forms of precipitated aluminium and, in the case of Cu, also to the neoformation of hydroxysulfate.展开更多
文摘Industrial activities such as smelting emissions,mineral combustion and industrial wastewater discharge might lead to copper pollution in the environment.This kind of copper pollution has harmful effects on aquatic o rganisms,plants and animals through direct or indirect exposure.However,the current understanding of the toxicity of copper is rather limited.Copper overload can perturb intracellular homeostasis and induce oxidative stress and e ven cell death.Recently,cuproptosis has been identified as a copper-dependent form of cell death induced by o xidative stress in mitochondria.We uncover here that zinc transporter 1(ZNT1)is an important regulator involved in cuproptosis.Firstly,we established the copper overload-induced cell death model with the overexpression of copper importer SLC31A1 in HeLa cells.Using this model,we conducted unbiased genome-wide CRISPR-Cas9 screens in cells treated with copper.Our results revealed a significant enrichment of ZNT1 gene in both library A and library B plasmids.Knocking out of ZNT1 in HeLa cells notably prevented cuproptosis.Subsequent knockout of metal transcription factor 1(MTF1)in ZNT1-deficient cells nearly abolished their ability to resist copper-induced cell death.However,overexpression of metallothionein 1X(MT1X)in the double-knockout cells could p artially restored the resistance to cuproptosis by loss of MTF1.Mechanistically,knockout of ZNT1 could promote MT1X expression by activating MTF1.As a consequence,the interaction between MT1X and copper was e nhanced,reducing the flow of copper into mitochondria and eliminating mitochondria damage.Taken together,this study reveals the important role of ZNT1 in cuproptosis and shows MTF1-MT1X axis mediated resistance to c uproptosis.Moreover,our study will help to understand the regulatory mechanism of cellular and systemic copper homeostasis under copper overload,and present insights into novel treatments for damages caused by both genetic copper overload diseases and environmental copper contamination.
文摘The bioleaching of molybdenum from its sulfide ore using a Mo-resistant thermophilic bacterium sulfolobus metallics combined with a membrane biological reactor（MBR） was studied.The experimental results showed that the concentration of Mo can be controlled by filter of the membrane in MBR and the toxicity of Mo to microorganism is decreased in the process of bioleaching.It was also evidenced that there were different leaching rates of Ni and Mo when the concentration of Mo was different.After leaching for 20 d in the MBR at Mo concentration of 395 mg/L,the leaching rates of Ni and Mo reached the maximum of 79.57% and 56.23% respectively under the conditions of 100 g/L of mineral density,65 ℃,pH=2 and 1.0 L/min of the aeration rate.While 75.59% Ni and 54.33% Mo were leached out in column without membrane under the same conditions.
文摘A novel cDNA sequencehtMT2, which encodes a type 2 metallothionein_like protein, was isolated from Helianthus tuberosus L. tuber cDNA library. The whole sequence is 509 bp, including an open reading frame (ORF) of 240 bp, a 5′ UTR of 62 bp and a 3′ UTR of 207 bp. Two genomic sequences covering the coding region ofhtMT2were cloned by PCR reaction. Sequence analysis revealed that the genomic sequences htMTG_1 of 986 bp and htMTG_2 of 982 bp were both composed of three exons and two introns. The deduced protein consisted of 79 amino acid residues with a predicted molecular weight of 7.8 ku (kD). Amino_terminal and carboxy_terminal domains contained 8 and 7 cysteine residues respectively, separated by a central cysteine free spacer. Sequence alignment revealed that the predicted protein ofhtMT2 was homologous to type 2 metallothioneins (MTs) of plants. Southern blotting analysis indicated that htMT2was encoded by a small multi_gene family in H. tuberosus genome. Northern blotting analysis showed that htMT2 transcripts were detected in stems, leaves and leafstalks, but no transcripts were detected in roots. The expression level in stems was the highest among the above tissues. Transcripts in stems were significantly reduced by Cu 2+ treatment. Judging from the homologies between the deduced HtMT2 and other type 2 plant metallothioneins as well as responses to metal ions, we believe thatwere cloned by PCR reaction. Sequence analysis revealed that the genomic sequences htMTG_1 of 986 bp and htMTG_2 of 982 bp were both composed of three exons and two introns. The deduced protein consisted of 79 amino acid residues with a predicted molecular weight of 7.8 ku (kD). Amino_terminal and carboxy_terminal domains contained 8 and 7 cysteine residues respectively, separated by a central cysteine free spacer. Sequence alignment revealed that the predicted protein ofhtMT2 was homologous to type 2 metallothioneins (MTs) of plants. Southern blotting analysis indicated that htMT2was encoded by a small multi_gene family in H. tuberosus genome. Northern blotting analysis showed that htMT2 transcripts were detected in stems, leaves and leafstalks, but no transcripts were detected in roots. The expression level in stems was the highest among the above tissues. Transcripts in stems were significantly reduced by Cu 2+ treatment. Judging from the homologies between the deduced HtMT2 and other type 2 plant metallothioneins as well as responses to metal ions, we believe that[ShtMT2 encodes a new type 2 metallothionein.
文摘Rice metallothionein-like protein (rgMT) shows characteristics of a three-section pattern composed of two highly conserved cysteine rich (CR) domains in the terminals and a spacer without cysteine (cys) residues in the center of the molecule. In this paper, the two CR domains and the spacer region were modeled by the distance geometry and homology methods separately. For the CR domains, twenty random models were generated for each cys combination based on the constraint conditions of CXC (C represents cys, X represents any amino acid other than cys), and CXXC motifs and a metal-sulfur chelating cluster. Four models for the N-terminal and two for C-terminal CR domain containing metal chelating structures formed by different combinations of cys were selected from 900 possible conformations. The GOR method was used to predict the secondary structure of the spacer region and its model was built by the homology method. After three parts of the protein were modeled, they were connected to form a three-dimensional structure model of rgMT. The whole conformation showed that rgMT could form two independent metal-sulfur chelating structures connected by a spacer peptide, without a structural or energy barrier for them to form two independent metal-chelating clusters just as mammalian metallothionein (MT) proteins. As all plant metallothionein-like (MT-L) proteins have the same primary structural characteristic, two CR domains connected by a spacer region, and many have the same cys arrangement pattern as rgMT, the three-dimensional structure model of rgMT will provide an important reference for the structural study of other plant MT-L proteins.
基金Project(51044007)supported by the National Natural Science Foundation of ChinaProject(08121018)supported by the Science and Technology Project of Taiyuan City,China+2 种基金Project(20091402110010)supported by the Doctoral Found of Ministry of Education of ChinaProject(2008029)supported by the Shanxi Province Foundation for Returned Scholars,ChinaProject(20093007)supported by the Young Subject-Leader Foundation and the Innovative Project for Outstanding Post-graduate of Shanxi Province,China
文摘The corrosion behaviours of die-cast AZ91D magnesium alloys were investigated in 0.1 mol/L sodium sulphate （Na 2 SO 4 ） solutions with different pH values. The corrosion rates, morphologies, and compositions of the corrosion products were studied by means of scanning electron microscopy （SEM）, Fourier transform infrared spectroscopy （FTIR）, and X-ray diffractometry （XRD）. The results indicate that the order of corrosion rates in Na 2 SO 4 solutions with various pH values is pH 2pH 4pH 7pH 9pH 12. The corrosion rates in acidic solutions are higher than those in alkaline solutions, and the corrosion products are mainly magnesium hydroxide （Mg（OH） 2 ） and hydrated sulphate pickeringite （MgAl 2 （SO 4 ） 4 ·22H 2 O）. The results also indicate that the solution pH can influence the corrosion rate and morphology of corrosion products. Chloride ions and sulphate ions have different pitting initiation time.
文摘With the progress of plant genome research, more than 50 plant metallothionein_like (MT_L) genes have been found, but only several MT_L proteins have been detected and no experimental structural information for MT_L proteins has been reported so far. Since detailed knowledge of the protein tertiary structure is required to understand its biological function, a method is needed to determine the structure of these proteins. In this study, the structural data of known mammal MT was used to determine the interatomic distance constraints of the CXC and CXXC motifs and the metal_sulfur chelating cluster. Then several possible MT conformations were predicted using a distance geometry algorithm. The statistical analysis was used to select those with much lower target function values and lower conformation energies as the predicted tertiary structural models of the cysteine_rich (CR) domains of these proteins. A suitable prediction method for modeling the CR domain of the plant MT_L protein was constructed. The accurately predicted result for the known structure of an MT protein from blue crab suggests that this method is practicable. The tertiary structures of CR domains of rape MT_L protein LSC54 was then modeled with this method.
文摘Bioleaching is regarded as an essential technology to treat low grade minerals,with the distinctive superiorities of lower-cost and environment-friendly compared with traditional pyrometallurgy method.However,the bioleaching efficiency is unsatisfactory owing to the passivation film formed on the minerals surface.It is of particular interest to know the dissolution and passivation mechanism of sulfide minerals in the presence of microorganism.Although bioleaching can be useful in extracting metals,it is a double-edged sword.Metallurgical activities have caused serious environmental problems such as acid mine drainage(AMD).The understanding of some common sulfide minerals bioleaching processes and protection of AMD environment is reviewed in this article.
基金Project(50774020) supported by the National Natural Science Foundation of China
文摘The leaching of low-sulfur Ni-Cu matte in acid-oxygen(CuSO4-H2SO4-O2)solution at atmospheric pressure was researched.This matte was obtained from high grade Ni-Cu matte by magnetic separation,which mainly contained Ni-Cu alloy and a small quantity of sulfides.The effects of temperature,agitation speed,oxygen flow rate,particle size,acid concentration and concentration of copper ion were studied.It is found that the matte particles are leached by shrinking core mechanism and the leaching process is electrochemically controlled.In a temperature range of 30-60℃,the surface reaction is rate-limiting step,with an apparent activation energy of 41.9 kJ/mol.But at higher temperature(70-85℃),the rate process is controlled by diffusion through the product layer,with an apparent activation energy of 7.3 kJ/mol.
基金Project supported by the Science and Technology Ministry of Spain (Nos.REN 2003-03615 and CGL2006-10233)
文摘The continued effect of the pyrite-tailing oxidation on the mobility of arsenic, lead, zinc, cadmium, and copper was studied in a carbonated soil under natural conditions, with the experimental plot preserved with a layer of tailing covering the soil during three years. The experimental area is located in Southern Spain and was affected by a pyrite-mine spill. The climate in the area is typically Mediterranean, which determines the rate of soil alteration and element mobility. The intense alteration processes that occurred in the soil during three years caused important changes in its morphology and a strong degradation of the main soil properties. In this period, lead concentrated in the first 5 mm of the soil, with concentrations higher than 1500 mg kg?1, mainly associated to the neoformation of plumbojarosite. Arsenic was partially leached from the first 5 mm and mainly concentrated between 5–10 mm in the soil, with maximum values of 1239 mg kg-1; the retention of arsenates was related to the neoformation of iron hydroxysulfates (jarosite, schwertmannite) and oxyhydroxides (goethite, ferrihydrite), both with a variable degree of crystallinity. The mobility of Zn, Cd, and Cu was highly affected by pH, producing a stronger leaching in depth; their retention was related to the forms of precipitated aluminium and, in the case of Cu, also to the neoformation of hydroxysulfate.
